Insect herbivory on an inland brackish wetland

Abstract

Standing crop measurements were made in emergent wetland vegetation following acute herbivory by 2 species of leaf-chewing caterpillars,Cisseps fulvicula (Ctenucidae) andAcronicta leporina (Noctuidae). Significant weight differences were found between grazed and ungrazed stands of alkali bulrush, cattail, Olney’s bulrush, and saltgrass, respectively. The greatest absolute removal was 2050 kg/ha (43%) in cattail stands and the smallest was 783 kg/ha (47%) in Olney’s bulrush. Mincral conlent of cattail leaf parts remaining after grazing was greater than that of similar but ungrazed stands, suggesting non-random feeding by these insects. Herbivory removed enough plant material to significantly change the standing crop and alter plant stand architecture of these 4 emergent species.